U.S. patent application number 10/268745 was filed with the patent office on 2003-04-24 for intake arrangement for multi-cylinder engine.
This patent application is currently assigned to NISSAN MOTOR CO., LTD.. Invention is credited to Kudo, Yuji, Murata, Masahiro.
Application Number | 20030075135 10/268745 |
Document ID | / |
Family ID | 19139057 |
Filed Date | 2003-04-24 |
United States Patent
Application |
20030075135 |
Kind Code |
A1 |
Kudo, Yuji ; et al. |
April 24, 2003 |
Intake arrangement for multi-cylinder engine
Abstract
An intake arrangement for a multi-cylinder internal combustion
engine of a vehicle which has a row of cylinders. The arrangement
includes an intake manifold, which includes a collector extending
along a direction of the row of the cylinders and a branch portion
communicated with the collector, a fuel pipe extending along the
collector, and a protector extending along the fuel pipe between
the branch portion and the fuel pipe. The fuel pipe is disposed at
a downstream end portion of the branch portion which allows air to
be introduced into the cylinders. The protector is secured to the
downstream end portion of the branch portion and deformable to
cover the fuel pipe upon an impact load being applied to the branch
portion.
Inventors: |
Kudo, Yuji; (Kanagawa,
JP) ; Murata, Masahiro; (Yokohama, JP) |
Correspondence
Address: |
FOLEY AND LARDNER
SUITE 500
3000 K STREET NW
WASHINGTON
DC
20007
US
|
Assignee: |
NISSAN MOTOR CO., LTD.
|
Family ID: |
19139057 |
Appl. No.: |
10/268745 |
Filed: |
October 11, 2002 |
Current U.S.
Class: |
123/184.42 |
Current CPC
Class: |
F02M 35/10321 20130101;
F02M 35/112 20130101; F02M 69/465 20130101; F02M 35/10111 20130101;
F02M 35/10144 20130101; F05C 2225/08 20130101; F02M 35/10354
20130101; F02M 2200/185 20130101; F02M 35/10216 20130101; F02M
69/46 20130101; F02M 61/145 20130101 |
Class at
Publication: |
123/184.42 |
International
Class: |
F02M 035/10 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 19, 2001 |
JP |
2001-321927 |
Claims
What is claimed is:
1. An intake arrangement for a multi-cylinder internal combustion
engine of a vehicle, the engine having a row of cylinders, the
arrangement comprising: an intake manifold including a collector
adapted to extend along a direction of the row of the cylinders and
a branch portion communicated with the collector, the intake
manifold being adapted to introduce air to the cylinders via the
collector and the branch portion, the branch portion having a
downstream end portion allowing the air to be introduced into the
cylinders; a fuel pipe disposed at the downstream end portion of
the branch portion, the fuel pipe extending along the collector;
and a protector secured to the downstream end portion of the branch
portion, the protector extending along the fuel pipe between the
branch portion and the fuel pipe, the protector being deformable to
cover the fuel pipe upon an impact load being applied to the branch
portion.
2. The intake arrangement as claimed in claim 1, wherein the
protector comprises a base wall fixed to the branch portion and a
cover wall bent relative to the base wall, a pair of opposed side
walls extending in a direction substantially perpendicular to the
base wall and the cover wall, and flanges outwardly bent relative
to the opposed side walls.
3. The intake arrangement as claimed in claim 2, wherein the
protector comprises a plurality of openings and a plurality of
beads disposed between the openings, the openings and the beads
extending across the base wall and the cover wall in a transverse
direction relative to a longitudinal direction of the
protector.
4. The intake arrangement as claimed in claim 3, wherein the cover
wall defines first ends of the openings and second ends of the
beads, the first ends being located closer to the base wall than
the second ends.
5. The intake arrangement as claimed in claim 4, wherein the cover
wall has a peripheral edge extending along the fuel pipe, a first
distance between the first ends and the peripheral edge of the
cover wall being larger than a second distance between the second
ends and the peripheral edge of the cover wall.
6. The intake arrangement as claimed in claim 3, wherein the beads
extend from an inner surface of the cover wall to a lesser extent
than the side walls.
7. The intake arrangement as claimed in claim 1, wherein the branch
portion comprises a protector mount to which the protector is
mounted, and a split induction portion inducing a split in the
branch portion upon the impact load being applied to the branch
portion, the protector mount being spaced from the split induction
portion so as to avoid the split.
8. The intake arrangement as claimed in claim 7, wherein the engine
comprises a cylinder head having intake ports through which the air
flows into the cylinders, the collector being adapted to be
disposed above the cylinder head and extend along the direction of
the row of cylinders, the branch portion having a generally U-shape
and including an upper branch and a lower branch which are joined
with each other at a bent portion of the U-shape, the branch
portion being adapted to connect the collector to the intake ports,
the lower branch including a first member having the protector
mount, a second member, a split surface on which the first and
second members being joined together, and a downstream end portion
in which the first member is located on an upper side of the
vehicle as compared to the second member, the protector mount being
disposed on an outer surface of the first member at the downstream
end portion of the lower branch, the split surface extending
substantially along the flow of the air flowing in the lower
branch, the split surface including a downstream end located in an
outer surface of the downstream end portion of the lower branch in
a circumferentially opposed relation to the protector mount.
9. The intake arrangement as claimed in claim 8, wherein the split
induction portion comprises the split surface and a step formed on
the first member upstream of the protector mount, the first member
having a reduced thickness on the upstream side of the step.
10. The intake arrangement as claimed in claim 9, wherein the upper
and lower branches are joined together by bolts and a snap-fit
assembly, the bolts being located closer to the engine than the
snap-fit assembly.
11. The intake arrangement as claimed in claim 7, wherein the
downstream end portion of the branch portion comprises an intake
port flange mounted to the cylinder head, the protector mount being
disposed upstream of the intake port flange, the protector mount
comprising a boss outward projecting from an outer surface of the
downstream end portion of the branch portion and a rib connecting
the boss and the intake port flange.
12. The intake arrangement as claimed in claim 7, wherein the
downstream end portion of the branch portion comprises an intake
port flange mounted to the cylinder head, the protector mount being
disposed upstream of the intake port flange, the protector mount
comprising a boss outward projecting from an outer surface of the
downstream end portion of the branch portion and a plurality of
ribs connecting the boss and the intake port flange.
13. The intake arrangement as claimed in claim 1, wherein the
intake manifold is made of resin material.
14. An intake arrangement for a multi-cylinder internal combustion
engine of a vehicle, the engine having a row of cylinders, the
arrangement comprising: an intake manifold including branch means
for allowing a flow of air to be divided into branch flows
introduced into the cylinders; pipe means for supplying fuel to the
cylinders on a downstream side of the branch means; and protector
means for preventing the pipe means from being deformed upon an
impact load being applied to the branch means, the protector means
being deformable to cover the pipe means upon the application of
the impact load.
15. The intake arrangement as claimed in claim 14, wherein the
protector means comprises control means for controlling deformation
of the protector means so as to bend in a direction substantially
perpendicular to the pipe means.
16. The intake arrangement as claimed in claim 15, wherein the
control means comprises means for preventing distortion of the
deformation of the protector means.
17. The intake arrangement as claimed in claim 14, wherein the
protector means comprises cooling means for cooling the protector
means by emitting heat transmitted from the pipe means to the
protector means.
18. The intake arrangement as claimed in claim 14, wherein the
branch means comprises split induction means for inducing a split
in the branch means upon the application of the impact load.
19. The intake arrangement as claimed in claim 18, wherein the
split induction means comprises split means for dividing the branch
means into portions.
20. The intake arrangement as claimed in claim 19, wherein the
split means divides the branch means into portions along the branch
flows in the branch means.
21. The intake arrangement as claimed in claim 18, wherein the
split induction means comprises means for bending the branch means
toward the pipe means.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to an intake arrangement for a
multi-cylinder internal combustion engine of a vehicle, and more
specifically to an intake arrangement made of resin material.
[0002] There have been conventionally proposed intake manifolds
which are made of not metal material such as aluminum but resin
material in order to reduce the cost and the weight.
SUMMARY OF THE INVENTION
[0003] The intake manifolds made of resin material, however, have
less rigidity as compared with intake manifolds made of metal
material. Therefore, if an impact load is applied to the engine
room upon vehicle collision and the intake manifold made of resin
material may become deformed, the deformed intake manifold will be
urged toward a fuel pipe adjacent thereto so that the fuel pipe is
deformed. Further, the intake manifold made of resin material will
be readily vibrated because of the less rigidity. If the vibration
produced in the intake manifold is transmitted to a fuel injector,
fuel sprayed from the fuel injector will be prevented from being
directed toward a target area of the fuel injection. This will
cause deterioration in combustion properties.
[0004] It would threrefore be desirable to provide an intake
arrangement for an internal combustion engine of a vehicle in which
a protector for a fuel pipe is used. The protector is deformed so
as to protect a fuel pipe upon applying an impact load to the
intake arrangement, such as at the occurrence of vehicle collision.
Owing to the deformation of the protector, the impact load applied
to the intake arrangement can be reduced, and the fuel pipe can be
prevented from being deformed. Further, it would be desirable to
provide an intake arrangement for an internal combustion engine of
a vehicle which can be enhanced in rigidity by using a protector
for a fuel pipe. The intake arrangement having the enhanced
rigidity can reduce vibration caused therein, serving for
preventing the fuel pipe and a fuel injector from suffering from
the vibration transmitted from the intake arrangement.
[0005] In one aspect of the present invention, there is provided an
intake arrangement for a multi-cylinder internal combustion engine
of a vehicle, the engine having a row of cylinders, the arrangement
comprising:
[0006] an intake manifold including a collector adapted to extend
along a direction of the row of the cylinders and a branch portion
communicated with the collector, the intake manifold being adapted
to introduce air to the cylinders via the collector and the branch
portion, the branch portion having a downstream end portion
allowing the air to be introduced into the cylinders;
[0007] a fuel pipe disposed at the downstream end portion of the
branch portion, the fuel pipe extending along the collector;
and
[0008] a protector secured to the downstream end portion of the
branch portion, the protector extending along the fuel pipe between
the branch portion and the fuel pipe, the protector being
deformable to cover the fuel pipe upon an impact load being applied
to the branch portion.
[0009] In a further aspect of the present invention, there is
provided an intake arrangement for a multi-cylinder internal
combustion engine of a vehicle, the engine having a row of
cylinders, the intake arrangement comprising:
[0010] an intake manifold including branch means for allowing a
flow of air to be divided into branch flows introduced into the
cylinders;
[0011] pipe means for supplying fuel to the cylinders on a
downstream side of the branch means; and
[0012] protector means for preventing the pipe means from being
deformed upon an impact load being applied to the branch means, the
protector means being deformable to cover the pipe means upon the
application of the impact load.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a perspective view of an intake arrangement for an
internal combustion engine, according to an embodiment of the
present invention;
[0014] FIG. 2 is an front view of the intake arrangement shown in
FIG. 1;
[0015] FIG. 3 is a side view of the intake arrangement shown in
FIG. 1
[0016] FIG. 4 is a plan view of a lower branch of an intake
manifold in the arrangement of FIG. 1;
[0017] FIG. 5 is a perspective view of the intake arrangement,
showing the lower branch to which a protector and a fuel pipe are
mounted;
[0018] FIG. 6 is a perspective view of the protector of FIG. 5;
[0019] FIG. 7 is an explanatory diagram of deformation of the lower
branch and the protector upon an impact load being applied to the
intake manifold; and
[0020] FIG. 8 is a vertical sectional view of the engine.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0021] Referring now to FIGS. 1-7, there is shown an arrangement
for a multi-cylinder internal combustion engine of a vehicle,
according to a preferred embodiment of the present invention. In
this embodiment, the arrangement is applied to a four-cylinder
engine. FIG. 8 shows engine 100 including cylinder block 102 and
cylinder head 104. Four cylinders are defined in cylinder block 102
so as to be arranged in a row. Cylinder head 104 is disposed on the
top of cylinder block 102. Cylinder head 104 has intake ports 106
corresponding to the cylinders. Intake valve 108 is disposed in
each of intake ports 106 and operated to open and close intake
ports 106.
[0022] The arrangement includes intake manifold 1, fuel pipe 4 and
protector 6 for fuel pipe 4, as better shown in FIG. 3. Intake
manifold 1 is made of resin material and allows air to be
introduced to the engine cylinders. As illustrated in FIGS. 1-3,
intake manifold 1 includes collector 2 and branch portion 3
communicated with collector 2. Collector 2 is disposed above
cylinder head 104 of engine 100 shown in FIG. 8 and allows a main
flow of the air. Collector 2 has a generally elongated cylindrical
shape extending along the row of cylinders. Branch portion 3
connects collector 2 to intake port 106 of each cylinder of engine
100 and allows the main flow of air in collector 2 to be divided
into branch flows each introduced into the cylinder via intake port
106. In this embodiment, branch portion 3 has four branches
corresponding to the four cylinders extending in a transverse
direction relative to the longitudinal axis of collector 2.
[0023] As illustrated in FIG. 3, branch portion 3 has a generally
U-shape. Branch portion 3 includes upper branch 9 and lower branch
10 which are joined with each other at bent portion 8 of the
U-shape. Upper branch 9 has downstream end portion 11 relative to
the air flow flowing through branch portion 3 into intake port 106,
and lower branch 10 has upstream end portion 12 relative to the air
flow. Downstream end portion 11 and upstream end portion 12 are
joined with each other with the combined use of bolts and so-called
snap-fit assemblies. Namely, as shown in FIG. 2, each of the
snap-fit assemblies is constituted of projection 13 and hole 15
which are engaged with each other. Projection 13 is formed at
upstream end portion 12. Hole 15 is formed in tab 14 projecting
from downstream end portion 11.
[0024] As illustrated in FIG. 4, lower branch 10 has bolt holes 16
for tap bolts B. Sleeve 17 which is made of resin material and has
an internal thread, is fixed into each of bolt holes 16. Each of
tap bolts B is screwed into sleeve 17 from a lower side of lower
branch 10 upon coupling lower branch 10 with upper branch 9. Each
of bolt holes 16 is located on the side closer to the engine than
each of the snap-fit assemblies, namely, on the upper side of FIG.
4. Bolt holes 16 are arranged substantially in line along the
longitudinal axis of collector 2. Lower branch 10 has a downstream
end portion formed with intake port flange 19. Intake port flange
19 is mounted to cylinder head 104 of engine 100 shown in FIG. 8.
The downstream end portion of lower branch 10, i.e., the downstream
end portion of branch portion 3, allows the air to be introduced
into the cylinders via intake port 106 of cylinder head 104.
Reference numeral 18 denotes a mount hole for fuel injector 5 shown
in FIG. 3.
[0025] Protector mounts 20, 20 for mounting protector 6 are
disposed on the downstream end portion of lower branch 10 but
upstream of intake port flange 19. Protector mounts 20, 20 are
disposed an outer surface of an upper side of the downstream end
portion of lower branch 10. Protector mounts 20, 20 are spaced from
and opposed to each other along the direction of the row of the
engine cylinders. Namely, protector mounts 20, 20 are located on
the left and right sides in FIG. 4. Each of protector mounts 20, 20
includes boss 21 and two opposed ribs 22. Boss 21 outward projects
from the outer surface of the downstream end portion of lower
branch 10 and spaced from intake port flange 19. Ribs 22 extend
between boss 21 and intake port flange 19 and connect them.
[0026] As illustrated in FIG. 3, protector 6 is secured to
protector mounts 20, 20 of lower branch 10 together with fuel pipe
4 having fuel injector 5. Fuel injector 5 is preassembled to fuel
pipe 4. Fuel pipe 4 is connected with a fuel tank via fuel tube 7
and supplies fuel from the fuel tank to fuel injector 5. Fuel pipe
4 extends along the longitudinal axis of collector 2, i.e., in the
direction of the row of engine cylinders. As illustrated in FIG. 5,
fuel pipe 4 has end portions 4A, 4A opposed to each other in the
longitudinal direction and general portion 4B extending between end
portions 4A, 4A. End portions 4A, 4A have rigidity larger than that
of general portion 4B. Fuel pipe 4 has mount 23 which is interposed
between protector 6 and protector mounts 20, 20. Fuel pipe 4 is
fixed to protector mounts 20, 20 via mount 23.
[0027] Specifically, as shown in FIG. 3, lower branch 10 includes a
pair of members 25 and 26 coupled with each other and split surface
24 disposed between the pair of members 25 and 26. At the
downstream end portion of lower branch 10, one member 25 is located
on an upper side of lower branch 10 and provided with protector
mount 20, and the other member 26 is located on a lower side of
lower branch 10. Namely, at the downstream end portion of lower
branch 10, one member 25 and the other member 26 are located on an
upper side of the vehicle and a lower side thereof, respectively.
Two members 25 and 26 are joined together at split surface 24 by
vibration welding. Split surface 24 extends substantially along the
flow of the air introduced into lower branch 10 and flowing to
intake ports 106 of cylinder head 104 of engine 100. Split surface
24 is curved toward member 26, namely, downwardly as viewed in FIG.
3. Split surface 24 has downstream end 24A disposed at the
downstream end portion of lower branch 10. Downstream end 24A is
located in the lower side surface of lower branch 10 in a
circumferentially opposed relation to protector mount 20 disposed
on the upper side surface of lower branch 10. Member 25 has step 27
formed on an outer surface thereof upstream of protector mount 20.
Member 25 has a reduced thickness on the upstream side of step 27
which is smaller than a thickness on the downstream side of step
27. Split surface 24 and step 27 act as a split induction portion
which induces a split in branch portion 3 upon an impact load being
applied to branch portion 3. Split surface 24 acts to divide lower
branch 10 into members 25 and 26 along the branch flows in lower
branch 10 as explained later. Step 27 acts to bend member 25 toward
fuel pipe 4 as explained later.
[0028] Upper branch 9 includes a pair of members 29 and 30 coupled
with each other and split surface 28 between the pair of members 29
and 30. Split surface 28 extends substantially in the direction of
the flow of the air introduced into upper branch 9. Two members 29
and 30 are joined together at split surface 28 by vibration
welding.
[0029] Protector 6 disposed between fuel pipe 4 and branch portion
3 has a generally L-shape as shown in FIG. 3. Protector 6 extends
along fuel pipe 4 over the longitudinal length of fuel pipe 4 and
the lateral width thereof perpendicular to the longitudinal length
as shown in FIG. 5. As illustrated in FIG. 6, protector 6 includes
base wall 35 and cover wall 36 which are integrally formed with
each other. Base wall 35 is fixed to protector mount 20 of lower
branch 10. Cover wall 36 is bent at a predetermined angle relative
to base wall 35. The predetermined angle may be about 90 degrees.
Protector 6 also has, at opposed ends thereof, side walls 37, 37
with flanges 38, 38. Side walls 37, 37 upward extend from cover
wall 36 in an opposed relation to each other and are connected with
base wall 35. Side walls 37, 37 are substantially perpendicular to
base wall 35 and cover wall 36. Flanges 38, 38 are outward bent at
upper ends of side walls 37, 37. Flanges 38, 38 are integrally
formed with side walls 37, 37. Protector 6 is formed by bending a
metal sheet.
[0030] A plurality of generally rectangular-shaped openings 39 are
formed in protector 6. Openings 39 are spaced from each other in
the longitudinal direction of protector 6. Each of openings 39
extends across base wall 35 and cover wall 36 in a transverse
direction relative to the longitudinal direction of protector 6. A
plurality of beads 40 are disposed between openings 39, which
extend across base wall 35 and cover wall 36 in the transverse
direction relative to the longitudinal direction of protector 6.
Beads 40 have a larger length than openings 39. Beads 40 are
provided by press forming so as to project from an inner surface of
L-shaped protector 6, namely, project upward in FIG. 3. Beads 40
extend from an inner surface of cover wall 36 to a lesser extent
than side walls 37. Namely, beads 40 have a height from the inner
surface of cover wall 36 which is smaller than a length of side
walls 37 of protector 6. The height of beads 40 is preset such that
beads 40 can be prevented from being contacted with fuel pipe 4
before flanges 38, 38 come into contact with opposed ends 4A, 4A of
fuel pipe 4 upon deformation of protector 6 as explained later.
Cover wall 36 defines one end 39A of each opening 39 and one end
40A of each bead 40, and base wall 35 defines an opposite end of
each opening 39 and an opposite end of each bead 40. Specifically,
cover wall 36 has a peripheral edge which extends in the
longitudinal direction of protector 6 on an opposite side of the
joint periphery connected with base wall 35. One end 39A of each
opening 39 and one end 40A of each bead 40 are located close to the
peripheral edge of cover wall 36. As shown in FIG. 6, distance L1
between one end 39A and the peripheral edge of cover wall 36 is
larger than distance L2 between one end 40A and the peripheral edge
of cover wall 36. In other words, one end 39A is located closer to
base wall 35 than one end 40A.
[0031] When the vehicle having the above-described arrangement
undergoes collision, a relatively large impact load F is applied to
branch portion 3 via the engine room as indicated in FIG. 3. The
application of large impact load F causes projection 13 and hole 15
of the snap-fit assembly to be disengaged from each other, and
causes sleeves 17 with bolts B to be fallen from bolt holes 16.
This permits U-shaped branch portion 3 to be divided at bent
portion 8 into upper branch 9 and lower branch 10. At this state,
lower branch 10 fixed to engine cylinder head 104 is restricted in
the displacement in the engine room, while upper branch 9 and
collector 2 are allowed to move therein. Lower branch 10 absorbs
the impact energy to be deformed into the state shown in FIG. 7. In
this state, lower branch 10 is bent at step 27 of upper member 25
toward fuel pipe 4 and split along split surface 24 such that upper
member 25 and lower member 26 are separated from each other at
split surface 24. Lower branch 10 bent is in contact with protector
6 and urges protector 6 such that cover wall 36 is bent toward fuel
pipe 4, i.e., leftward in FIG. 7. Protector 6 is plastically
deformed into a bent state as shown in FIG. 7. At the bent state,
fuel pipe 4 is covered by protector 6 over the longitudinal length
of fuel pipe 4 and the lateral width thereof.
[0032] If protector 6 is further deformed to come closer to fuel
pipe 4, flanges 38, 38 of protector 6 will be brought into contact
with opposed ends 4A, 4A of fuel pipe 4. Even in such a condition,
since opposed ends 4A, 4A have the increased rigidity, fuel pipe 4
can be prevented from being readily deformed at opposed ends 4A, 4A
due to the contact with flanges 38, 38. Further, owing to the
preset height of beads 40 which is smaller than that of side walls
37, 37, beads 40 can be prevented from the contact with fuel pipe 4
before flanges 38, 38 are contacted with opposed ends 4A, 4A of
fuel pipe 4.
[0033] If protector 6 undergoes a relatively small impact load upon
being contacted with lower branch 10, protector 6 will be free from
plastic deformation and will be elastically deformed to absorb the
impact energy.
[0034] With the above-described arrangement, upon application of a
relatively large impact load to branch portion 3 of intake manifold
1 in such a case as vehicle collision, the impact energy can be
absorbed by deformation of protector 6 so that fuel pipe 4 can be
protected from deformation as explained above.
[0035] Further, the impact energy also can be absorbed and reduced
by three-stage split of branch portion 3. The three stages of split
of branch portion 3 are as follows: at the first stage upper branch
9 and lower branch 10 are separated at bent portion 8 of branch
portion 3; at the second stage lower branch 10 is bent at step 27
and separated along split surface 24; and at the third stage
protector 6 is deformed by lower branch 10 bent and separated. This
serves for ensuring protection of fuel pipe 4 upon application of
the impact load. In addition, the split of lower branch 10 is
conducted at step 27 and split surface 24 which act as the split
induction portion. This can prevent protector mount 20, 20 from
being deformed due to the impact load applied to branch portion 3.
Therefore, protector 6 fixed to protector mount 20, 20 can perform
protection of fuel pipe 4 upon application of the impact load.
[0036] Further, with the arrangement of protector 6, the rigidity
of intake manifold 1 made of resin material can be enhanced, and
vibration of intake manifold 1 which occurs during an ordinary
operation of the vehicle can be reduced. Furthermore, protector 6
is secured together with fuel pipe 4 and fuel injector 5 to the
downstream end portion of lower branch 10 at the opposed ends
spaced from each other in the direction of the row of engine
cylinders. This can prevent vibration of fuel pipe 4 and fuel
injector 5, serving for suppressing offset of the target area where
fuel injection is provided.
[0037] Protector 6 can be readily formed by bending the metal
sheet, whereby the production cost can be saved. Further, openings
39 and beads 40 alternately arranged in protector 6 cooperate to
provide protector 6 with appropriate rigidity and control
deformation of protector 6 so as to bend substantially
perpendicular to a direction of the longitudinal length of fuel
pipe 4. Furthermore, as described above, distance L1 between the
peripheral edge of cover wall 36 and one end of each opening 39
which is located in cover wall 36 is set larger than distance L2
between the peripheral edge of cover wall 36 and one end of each
bead 40 which is located in cover wall 36. The setting of distance
L1 relative to distance L2 can control deformation of protector 6
so as to uniformly proceed along the longitudinal direction of
protector 6, i.e., the direction of the row of engine cylinders,
without distortion or twisting relative to the longitudinal
direction. Further, with the provision of openings 39 in protector
6, heat transmitted from fuel pipe 4 and fuel injector 5 adjacent
to protector 6 to protector 6 can be effectively emitted to the
atmosphere. Therefore, protector 6 can be improved in cooling
efficiency and can act as an effective cooling member for intake
manifold 1, fuel pipe 4 and fuel injector 5. Meanwhile, beads may
be formed to project from an outer surface of L-shaped protector 6
toward lower branch 10. However, beads 40 of this embodiment which
upward project from the inner surface of L-shaped protector 6 is
preferable from the viewpoint of layout, wherein a space between
protector 6 and lower branch 10 can be reduced as compared with
protector 6 having the beads projecting from the outer surface.
[0038] The combined use of bolts B and the snap-fit assemblies for
coupling upper branch 9 and lower branch 10 can improve efficiency
of the coupling operation of upper branch 9 and lower branch 10 and
can limit the number of bolts to the minimum. Further, with the
combined use of bolts B and the snap-fit assemblies, the coupling
force of upper branch 9 and lower branch 10 can be maintained to a
required extent. As a result, U-shaped branch portion 3 can be
separated at bent portion 8 into upper branch 9 and lower branch 10
upon a relatively large impact load being applied to branch portion
3. The above-described three-stage split of branch portion 3 can be
performed to gradually absorb the impact energy and ensure
protection of fuel pipe 4 from deformation due to the impact
energy.
[0039] Further, generally U-shaped branch portion 3 can serve for
reducing a size of the whole intake manifold 1. In addition, intake
manifold 1 can be readily produced using branch portion 3 formed by
upper and lower branches 9 and 10 coupled together, in which upper
and lower branches 9 and 10 are composed of one pair of coupled
members 29 and 30 and the other pair of coupled members 25 and 26,
respectively.
[0040] Furthermore, protector mount 20, 20 constituted of boss 21
and ribs 22 can be formed by a reduced amount of resin material but
can have rigidity to endure an impact load applied to branch
portion 30.
[0041] This application is based on prior Japanese Patent
Application No. 2001-321927 filed on Oct. 19, 2001, the entire
content of which is hereby incorporated by reference.
[0042] Although the invention has been described above by reference
to a certain embodiment of the invention, the invention is not
limited to the embodiment described above. Modifications and
variations of the embodiment described above will occur to those
skilled in the art in light of the above teachings. The scope of
the invention is defined with reference to the following
claims.
* * * * *